Several full size ice chests FULL of ice and big watermelons.

Lots of iced green tea and lemonade- better for heat than soda-- maybe with sherbet scooped in? about 10 gallons

2 bottles of water per person

2 6 foot hero sandwiches OR wraps

1 pound assorted chips per 10-12, 1 pint dips per pound- some could be grown up, like hummus

potato, pasta or couscous or rice salad and slaw, 2 gallons each